This invention pertains to indirect area lighting devices and more particularly to overhead luminaire, or troffer, lighting fixtures and associated housings, reflectors, and methods for providing area lighting.
Lighting devices including one or more light emitters and associated reflectors for distributing light in an area are generally known in the art for various applications such as indoor and exterior lighting in buildings and automobiles. Such devices may be referred to generally as a luminaire or a troffer in some applications. Conventional luminaire devices typically house one or more light sources such as incandescent bulbs or light emitting diode emitters. Light from each light source travels away from the luminaire toward an area to be illuminated. In many applications, conventional devices allow light from the light source to travel directly to the area to be illuminated. However, such direct illumination may cause one or more areas of high intensity, or bright spots, near the light source when the lighting fixture is viewed from the illumination area. These variations in intensity can be unpleasing to the eye and may cause uneven light distribution, resulting in more illumination near the light source and less illumination farther away from the light source.
To overcome these problems, others have attempted to provide lighting fixtures including housings having one or more reflectors and/or lenses positioned near a light source in an attempt to more evenly distribute emitted light. Such reflectors can cause some of the emitted light to travel in a more even distribution away from the light source. However, conventional lighting fixtures of this type generally reduce the optical efficiency of the lighting device. In many applications, as little as 50% of the lighting energy emitted from each light source becomes incident upon the area to be illuminated. Such losses are inefficient and are generally undesirable. To overcome this problem, some conventional luminaire devices allow direct light illumination from the light source. However, as previously noted, emission of light directly from the light source into the illumination area is generally undesirable in many applications. Thus, conventional devices struggle to balance reduction or elimination of direct light with optical efficiency.
What is needed then are lighting devices, reflectors, housings and methods of lighting to improve optical efficiency while using indirect illumination.